Gangstarr may never have topped the charts, but they helped spearhead an underground hip-hop movement that is vital to this day. From their early jazz exercises ("Manifest," "Just to Get a Rep) to their latter proto boom bap ("Mass Appeal," "You Know My Steez"), the group never let up, and never sold out. Guru's monotone flow is one of the most recognizable in hip-hop, and helped spearhead roughneck rap, while DJ Premier is among the genre's most celebrated producers. "Tha Squeeze" and "Natural" are unreleased and stand up well next to the classics.